title: Risk factors for acetabular retroversion in developmental dysplasia of the hip: does the Pemberton osteotomy contribute?
abstract: BACKGROUND
  The purpose of this study was to investigate residual acetabular retroversion after skeletal maturity in patients with Pemberton osteotomy.
  
  
  METHODS
  We compared 40 hips in 36 patients treated with a Pemberton osteotomy (Pemberton group) and 30 hips in 26 patients treated only with a Pavlik harness (Rb group) for developmental dysplasia of the hip. The average age at operation in the Pemberton group was 94.5 months and the follow-up duration was 151.8 months. Radiographic parameters included the acetabular index (α angle) and the center-edge angle of Wiberg, preoperatively and at skeletal maturity. We examined the crossover sign (COS) at the latest follow-up as a sign of acetabular retroversion (AR). We compared the parameters between the two groups and examined the risk factors for acetabular retroversion using a multivariate Cox model.
  
  
  RESULTS
  A COS (+) was significantly more frequent in the Pemberton group compared to the Rb group [15 hips (37.5%) vs 3 hips (10%); p = 0.0077]. In the Pemberton group, the average age at operation in COS (+) hips was significantly older than that in COS (-) hips (126.9 vs 72.8 months; p = 0.0005). The preoperative α angle did not vary between hips with and without COS; however, the postoperative α angle was significantly smaller in COS (+) hips. A multiple logistic regression analysis for prediction of COS (+) showed that the age at operation and the amount change of α angle were significant predictors for COS (+) hips. The cut-off of the age at operation was 7 years and 9 months old.
  
  
  CONCLUSIONS
  AR was present in 37.5% of the hips in the Pemberton group after skeletal maturity. Remodeling of acetabular version was observed in younger patients; however, hips in older patients (>8 years) at the time of operation and greater degrees of correction tended to result in AR.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan, m_akkey@ortho.med.kyushu-u.ac.jp.
authors.forename: Mio
authors.initials: M
authors.lastname: Akiyama
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nakashima
authors.forename: Masanobu
authors.initials: M
authors.lastname: Oishi
authors.forename: Taishi
authors.initials: T
authors.lastname: Sato
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hirata
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hara
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000601:surgery; D016723:Bone Remodeling; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D010027:Osteotomy / Q000379:methods*; D011183:Postoperative Complications / Q000453:epidemiology*; D015995:Prevalence; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome